The disclosure relates generally to a distributed antenna system (DAS) and more particularly to techniques for amplifying multiple wireless channels in a DAS.
Wireless customers are increasingly demanding digital data services, such as streaming video signals. At the same time, some wireless customers use their wireless communications devices in areas that are poorly serviced by conventional cellular networks, such as inside certain buildings or areas where there is little cellular coverage. One response to the intersection of these two concerns has been the use of DASs. DASs include remote units configured to receive and transmit communications signals to client devices within the antenna range of the remote units. DASs can be particularly useful when deployed inside buildings or other indoor environments where the wireless communications devices may not otherwise be able to effectively receive radio frequency (RF) signals from a signal source.
In this regard, FIG. 1 illustrates distribution of communication services to remote coverage areas 100(1)-100(N) of a DAS 102, wherein ‘N’ is the number of remote coverage areas. These communication services can include cellular services, wireless services, such as RF identification (RFID) tracking, Wireless Fidelity (Wi-Fi), local area network (LAN), wireless LAN (WLAN), wireless solutions (Bluetooth, Wi-Fi Global Positioning System (GPS) signal-based, and others) for location-based services, and combinations thereof, as examples. The remote coverage areas 100(1)-100(N) may be remotely located. In this regard, the remote coverage areas 100(1)-100(N) are created by and centered on remote antenna units (RAUs) 104(1)-104(N) connected to a head-end equipment (HEE) 106 (e.g., a head-end controller, a head-end unit (HEU), or a central unit). The HEE 106 may be communicatively coupled to a signal source 108, for example, a base transceiver station (BTS) or a baseband unit (BBU). In this regard, the HEE 106 receives downlink communications signals 110D from the signal source 108 to be distributed to the RAUs 104(1)-104(N). The RAUs 104(1)-104(N) are configured to receive the downlink communications signals 110D from the HEE 106 over a communications medium 112 to be distributed to the respective remote coverage areas 100(1)-100(N) of the RAUs 104(1)-104(N). In a non-limiting example, the communications medium 112 may be a wired communications medium, a wireless communications medium, or an optical fiber-based communications medium. Each of the RAUs 104(1)-104(N) may include an RF transmitter/receiver (not shown) and a respective antenna 114(1)-114(N) operably connected to the RF transmitter/receiver to wirelessly distribute the communication services to client devices 116 within the respective remote coverage areas 100(1)-100(N). The RAUs 104(1)-104(N) are also configured to receive uplink communications signals 110U from the client devices 116 in the respective remote coverage areas 100(1)-100(N) to be distributed to the signal source 108. The size of each of the remote coverage areas 100(1)-100(N) is determined by the amount of RF power transmitted by the respective RAUs 104(1)-104(N), receiver sensitivity, antenna gain, and RF environment, as well as by RF transmitter/receiver sensitivity of the client devices 116. The client devices 116 usually have a fixed maximum RF receiver sensitivity, so that the above-mentioned properties of the RAUs 104(1)-104(N) mainly determine the size of the respective remote coverage areas 100(1)-100(N).
In a non-limiting example, the RAUs 104(1)-104(N) are configured to wirelessly distribute the downlink communications signals 110D to the client devices 116 based on long-term evolution (LTE) technology. In this regard, the downlink communications signals 110D may occupy different LTE channels of respective bandwidths. For example, a first LTE channel occupies a respective bandwidth of five megahertz (5 MHz) while a second LTE channel occupies a respective bandwidth of twenty megahertz (20 MHz). In this regard, if the downlink communications signals 110D are transmitted in the first LTE channel and the second LTE channel with a power level P, a channel power density of the first LTE channel is P/(5 MHz), while a channel power density of the second LTE channel will be P/(20 MHz). In this regard, the first LTE channel has a higher channel power density than the second LTE channel. As a result, the downlink communications signals 110D transmitted in the first LTE channel may achieve a longer coverage range than the downlink communications signals 110D transmitted in the second LTE channel. As such, it may be desirable to transmit the downlink communications signals 110D in both the first LTE channel and the second LTE channel with similar coverage range.
No admission is made that any reference cited herein constitutes prior art. Applicant expressly reserves the right to challenge the accuracy and pertinency of any cited documents.